2. Stress Analysis of Differential Housing Cover Manu- Factured by Pressure Die Casting
Process
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Engineering and Technology, 6(8), 2015, pp. 70-77.
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_______________________________________________________________
1. INTRODUCTION
During industrial visit, I came across a problem normally faced by the production
units.
The parts manufactured in industry involve different processes and often several
parts are rejected. Some times the number of rejection is far greater than expected. So,
a question came to my mind of how to reduce the number of rejection. After several
visit, I selected differential housing cover as study part.
2. PROBLEM DEFINITION
A differential housing cover (Figure 1) (part made by scooter India for engine gear
cover) manufactured by pressure die casting process is subjected to uniform pressure
of 0.245 MPa (pressure applied by the piston). This DH cover is fixed at the back and
pressure is applied from the front. The material of the DH cover is AISI 132 and its
composition is given below. This DH cover is stress analyzed to investigate the reason
for the number of failure and further it is optimized to reduce the number of rejection.
Figure 1 Differential housing cover (DH cover)
3. PROPERTIES OF AISI-132 MATERIAL
Tensile strength- 35000 psi
Hardness BHN (10/500)- (80-110) kg/mm^2
Modulus of elasticity- 10.3*10^6 psi
Density- 2.66 gm/cc
Elongation- 3.5%
Upper melting point- 582°C
Lower melting point- 522°C
3. Ravindra k. Singh, Er. Mohd. Shadab Ansari and Mr. A. k. Rathore
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4. COMPOSITION OF AISI-132
Cu (1.75-2.5)% , Mg 0.34% , Si (11-12.5)% , Fe (max 0.3)% , Mn 0.5% , Ni 0.35 , Zn
1.4% , Pb 0.15% , Sn 0.1% , remaining Aluminium
5. OBJECTIVE OF THE ABOVE PROBLEM
Modelling and stress analysis of components made by pressure die casting
To minimise defects that are produced during casting.
To minimise number of casting products which are rejected during pressure die
casting.
Quality issue can be handled and related solutions can be proposed
6. DIMENSIONS OF DHC
Dimension of DHC is obtained from the drawing collected from the Scooter India Pvt.
Ltd. Company.
Figure 2 Dimension of Differential housing cover (DH cover) (courtesy scooter’s India pvt
ltd.)
7. MODELLING IN SOLIDWORKS
Figure 3 Assembly of Differential Housing Cover modelled in Solid wor
4. Stress Analysis of Differential Housing Cover Manu- Factured by Pressure Die Casting
Process
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8. MESHING
The process of dividing a body into small bodies is call meshing. The small bodies are
called elements, or finite elements. The simulation method is thus called finite element
simulation. The basic idea of finite element methods is to divide a body of rather
complicated geometry into smaller elements of simple geometry, and the elements are
assumed to be connected to each other through nodes. The element's geometry is so
simple that a set of equations may be established easily for each element. All
equations are then solve simultaneously for the displacements. Strains are then
calculated from the displacements. And stresses are in turn calculated from the strains.
Figure 4 Figure showing meshing of front part of assembly in ANSYS
9. APPLICATION OF PRESSURE
Figure 5 Figure showing application of pressure in the front part of assembly in ANSYS
5. Ravindra k. Singh, Er. Mohd. Shadab Ansari and Mr. A. k. Rathore
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10. APPLICATION OF SUPPORT
Figure 6 Figure showing application of support in the back part of assembly in ANSYS
11. EQUIVALENT STRESSES
Figure 7 Figure showing equivalent stresses in the assembly in ANSYS
12. DEFORMATION
Figure 8 Figure showing deformation in the assembly in ANSYS
6. Stress Analysis of Differential Housing Cover Manu- Factured by Pressure Die Casting
Process
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13. RESULTS DISCUSSION AND OPTIMIZATION
The following conclusion may be drawn from the above results
1. Von misses stresses are found to be satisfactory except near the opening in the middle
of the DHC
2. Total deformation is near to zero and may be reduced further.
3. The stresses found above are responsible for the cracks and other deformation which
is confirmed by the Figure 9 given below.
Figure 9 figure showing rejected DHC
14. REJECTED COMPONENTS
As we visited scooters India Pvt. Limited we came to know about these data:
Production of DH cover per month: 1450
Dispatch: 1440
Rejected parts: 10
15. OPTIMIZATION
Optimization is process minimization of rejected parts by reducing the equivalent
stresses on it and making the deformation negligible. To achieve this task , the
thickness of the base plate is varied and again their stresses and deformation are
computed. The process goes on like this
Step1. Making model of base plate of different thickness like 3.5, 4.0, 4.5 and 5mm
respectively.
Step2: Importing these assembly files into ANSYS workbench
Step 3: meshing of assembly
Step4: Equivalent stresses and Deformation of plate thickness =3.5mm
Step5: Equivalent stresses and Deformation of plate thickness = 4 mm
Step6: Equivalent stesses and Deformation of plate thickness = 4.5 mm
Step7: Equivalent stesses and Deformation of plate thickness = 5 mm
Step8: Results of equivalent stresses and deformation are compiled
7. Ravindra k. Singh, Er. Mohd. Shadab Ansari and Mr. A. k. Rathore
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Table 1 showing the variation of deformation and equivalent stress with respect to change in
thickness of base plate
S No Thickness(Mm) Deformation(M)
Equivalent
stress(N/m2
)
1 3 4.12E-07 5.23E+06
2 3.5 7.25E-07 6.11E+06
3 4 4.31E-07 6.69E+06
4 4.5 5.40E-07 4.73E+06
5 5 7.01E-07 5.76E+06
Step9: study the variation of equivalent stresses with the change in thickness of base
plate
Figure 10 Graph showing the variation of Equivalent stresses and thickness of base plate.
Step 10: Study the variation of deformation with the change in thickness of base plate
Figure 11 Graph showing the variation of deformation and thickness of base plate.
8. Stress Analysis of Differential Housing Cover Manu- Factured by Pressure Die Casting
Process
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16. CONCLUSION
It is concluded from the above results that Differential Housing Cover (part
manufactured by the Scooter India Private Limited.) posses Von Misses stresses.
Their values are found to be satisfactory except near the opening in the middle of
DHC
The Total deformation is negligible and may be reduced further.
The stresses found above are responsible for the cracks and other deformation which
is confirmed by the figure 6.1 given above.
It is concluded from the results of the Equivalent stresses with the variation in the
thickness of the base plate as shown in figure 10 that least maximum Equivalent
stress is of the base plate with thickness 4.5 mm
It is also concluded that the total deformation with the variation in the thickness of the
base plate as shown in the figure 11 is least when plate thickness is 4 mm.
The thickness of base plate may be taken as 4.5 mm (which is optimized value) as the
results obtained during stress analysis shown in the figure 10 and 11 are confirming
to this results.
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